Indicator

ABSTRACT

A composite indicator for obtaining a digital or alpha numeric readout as well as a dial type readout with provision for adjusting the output by dialing in certain corrections.

United States Patent Burns [451 Oct. 3, 1972 1 INDICATOR [72] Inventor:Harold S. Burns, 38 Greengate Road, Falmouth, Mass. 02540 [22] Filed:Nov. 3, 1970 211 Appl. No.: 86,419

[52] US. Cl. ..340/316, 340/27 NA [51] Int. Cl ..G09f 9/00 [58] Field ofSearch ...340/212, 27 R, 27 NA, 27 AT,

[56] References Cited UNITED STATES PATENTS Mulligan ..340/187 3,350,70510/1967 Bendicsen ..340/212 3,525,091 8/1970 Lally ..340/324 2,537,08610/1970 Andresen ..340/27R Primary Examiner-Thomas B. HabeckerAttorney-Barlow & Barlow [57] ABSTRACT A composite indicator forobtaining a digital or alpha numeric readout as well as a dial typereadout with provision for adjusting the output by dialing in certaincorrections.

2 Claims, 3 Drawing Figures PATENTEDUCT 3 I972 3 696, 385

FIGI

\ I I IIIIIIIIIIIfi 20 //0 COMPASS CARD F l G. 2

DIGITAL I 40 42 DISPLAY7 DIFFERENTIAL DECODER 30 SYNCHRO 36 3 ENCODERDRIVER U [H] 3.2 L DIRECTIONAL AMPLIFIERJ /35 22 25 SENSING a sERvo I oIvIEANs IvIoToR 1 RECEIVING SHAFT 34 F G 3 HAROLD s. BURNS ATTORNEYSINDICATOR BACKGROUND OF THE INVENTION This invention basically relatesto a display apparatus or indicator of composite type for a system inwhich direction, heading or bearing are involved and provides not onlydigital or alpha numeric readout but dial readout. Considering theapplication in a compass system, it has been very common in the pastaboard ships to utilize either magnetic compass cards or gyro energizedcompass cards for steering information that is displayed to thehelmsman. As a result the helmsman has become quite accustomed towatching the compass card or dial rotate in response to changes indirection of the ships head. A conventional dial used in this system isgraduated in at least one degree graduations over a 360 circle and ismarked numerically in at least ten degree spaces. This means that theperson visualizing this type of information mentally has to compute theactual reading in his mind, that is, to whether the graduation that heis looking at is 2, 24 or what have you since the graduations in betweenthe prime numerically marked graduations are not indicated. It would behelpful, therefore, to have an immediate translation of the reading thatis being seen by the user so that immediate interpretation can be had.In the past a number of devices have been used to aid one viewing a dialsuch as a compass dial and these have taken the form of primarily amanually adjusted set of lines into which a pointer should be placed tosteer the correct course should the device be located on a movingvehicle. Some aircraft repeaters utilize this principle. Additionallymagnifying devices aid a viewer and are in common use.

Many other applications of the indicator suggest themselves since theonly limitation is the parameter that is sensed. Broadly, therefore, theindicator may provide information such as liquid level in a tank,temperature, salinity, cable length, and a variety of angularinformation readouts.

SUMMARY OF THE INVENTION A display apparatus is provided which obtains adial readout as well as a digital or alpha-numeric readout. The dialreadout and the character/numeral readout are located in close proximityto each other so that if one is looking directly at one readout, by avery slight angular shift of a persons eye, he can direct his attention'to the secondary readout device. Also in certain types of displayapparatus it is advantageous to limit the field of view of anyparticular source of information and to this end the present displayapparatus limits the field of view of the dial indicator preferably toapproximately a third of a circle so that only a partial segment of thecircle is being viewed at any one time and the visual perception thatmust be obtained by the person looking at the information is much easiertherefore to abstract.

DESCRIPTION OF THE DRAWING FIG. 1 is a elevational view of the face ofthe display apparatus of the invention in the preferred form thereof;

FIG. 2 is a sectional view taken on lines 2-2 of FIG. 1; and

FIG. 3 is a block schematic diagram showing matter in which the tworeadout devices may operate.

DESCRIPTION OF THE PREFERRED EMBODIMENT It will be seen that theindicator of this invention is basically contained in a case 10 whichmay be centrally divided into two sections, there being an upper section11 with a viewing window 12 and a lower section 13 with a viewingwindow- 14. Also located within the lower section 13 may be accessorydevices in the form of knobs to provide a plurality of desiredfunctions. If the device is utilized as a directional indicator for acompass system, then, for example, a graduated dial 15 may be providedas a variation correction device and a second dial and knob 16 may beprovided to control the amount of illumination provided to the readoutsystem.

Within the housing and mounted on a shaft 20 is a graduated dial 22,which if used as a compass card or directional indicator is graduated indegrees of a circle from O to 360 and which may be provided withcardinal points 23 and intercardinal points 24 to aid the user inrecognizing the information displayed. It will be seen particularly byreferring to FIG. 2 that only a portion of the dial 22 is beingdisplayed through the viewing port 12. This arrangement permits the userto view only that section of information which is usable to him andwhich is readable by the index pointer 26. Located within the lower part13 of the housing are a plurality of alpha numeric or digital displays28 which are mounted in a fashion to be seen through the viewing port14. The arrangement of the displays 28 is such that they are locatedeffectively over the unused portion of the dial 22 thus making the twoviewing ports in close proximity to each other which aids the viewer inwatching two displays with very little eye shift.

The apparatus may be suitably powered by a sensing means shown in FIG. 3as a block 30, which measures a varying parameter such as a directionalheading. From this particular sensing means a differential synchro 32may be placed having a shaft 33 protruding therefrom to a knob 34 tochange the :angular information that is presented to its input. Theoutput of the differential synchro is fed to a control transformer orreceiving synchro 35. The output thereof is suitably amplified anddrives a servo motor (indicated by block 36) and the rotative outputdrives shaft 20 which then may be directly coupled to the dial 22 andintermediately coupled through a shaft 38 to an encoder 40. The encoderis essentially an analog to digital converter to change the shaft angleof the shaft 37 to digital logic. The encoder can take a variety offorms, one form being a housing having a plurality of individualsegments which are contacted by a brush driven by the shaft 38. In thisfashion the brushes perform a switching operation when the shaft rotatesonto a different segment, there being a sufficient number of segments toprovide discreet switch positions, and in this case 360 switchpositions. Various combinations of segment switching in a plurality ofswitching paths can be made to produce the proper coding required as iswell known to those skilled in the digital display art. Other types ofencoders may be used as, for example, an optical encoder where alternateopaque and transparent spots replace the actual segments and brushes arereplaced by photo-conductors. Following the encoder 40 is a decoderdriver 42 whose purpose is .to decode the encoded shaft angle to producethe proper sequence of currents to operate the displays. Again, avariety of decoder driver arrangements can be utilized; for example, afour-line BCD code and decoder driver will change the encoderinformation to drive properly the digital display devices 28 so that onewill display in units, one device will display in tenths and the otherinhundreds.

It is helpful if the encoder that is utilized has an unambiguous outputand produces a readout that corresponds to a given angle, and if theshaft is turned, the readout holds the last reading until it has turnedmore than one half of the space between degrees and then switches to thenext full degree. In this way withvan unambiguous output it neverbecomes hung, up between two numbers and read either the wrong nothingor some meaningless number.

Through the combination of the digital display and the dial display, theheading of a vehicle as, for example, a ship can be observed as aconventional compass card dial and a digital display.

I claim:

1. An indicator display for a compass system comprising a case, saidcase having one wall with a pair of juxtaposed openings with transparentmeans forming viewing windows, a graduated dial having peripheral scaledivisions, said dial mounted on a shaft to rotate therewith, the axis ofsaid shaft located to one side of an edge of and behind one opening todisplay a sector only of said dial, a digital readout means locatedbehind the other viewing window.

2. A composite indicator display apparatus for a compass systemcomprising a disc compass card'having circumferential scale divisionsadjacent its periphery, said card being mounted on a Shaft, a case, saidcase enclosing said card and shaft, said case having one wall providedwith a pair of openings adjacent, digital readout means mounted adjacentthe central portion of the disc compass card and viewable through one ofsaid openings, a segmental portion of the disc compass card beingviewable through the other opening, an edge of said other opening beinglocated above the axis of said shaft and means rotating said card andactuating said digital readout whereby duplicate readings may beobtained by the card and readout respectively.

1. An indicator display for a compass system comprising a case, saidcase having one wall with a pair of juxtaposed openings with transparentmeans forming viewing windows, a graduated dial having peripheral scaledivisions, said dial mounted on a shaft to rotate therewith, the axis ofsaid shaft located to one side of an edge of and behind one opening todisplay a sector only of said dial, a digital readout means locatedbehind the other viewing window.
 2. A composite indicator displayapparatus for a compass system comprising a disc compass card havingcircumferential scale divisions adjacent its periphery, said card beingmounted on a shaft, a case, said case enclosing said card and shaft,said case having one wall provided with a pair of openings adjacent,digital readout means mounted adjacent the central portion of the disccompass card and viewable through one of said openings, a segmentalportion of the disc compass card being viewable through the otheropening, an edge of said other opening being located above the axis ofsaid shaft and means rotating said card and actuating said digitalreadout whereby duplicate readings may be obtained by the card andreadout respectively.